Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932504Ab3COUtD (ORCPT ); Fri, 15 Mar 2013 16:49:03 -0400 Received: from mail-qa0-f48.google.com ([209.85.216.48]:45918 "EHLO mail-qa0-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932386Ab3COUtB (ORCPT ); Fri, 15 Mar 2013 16:49:01 -0400 MIME-Version: 1.0 In-Reply-To: <20130315203123.GA28128@kroah.com> References: <20130315132607.GA4565@quad> <20130315203123.GA28128@kroah.com> Date: Fri, 15 Mar 2013 21:49:00 +0100 Message-ID: Subject: Re: [PATCH] perf,x86: fix kernel crash with PEBS/BTS after suspend/resume From: Stephane Eranian To: Greg KH Cc: LKML , Linus Torvalds , Peter Zijlstra , "mingo@elte.hu" , Thomas Gleixner , Andrew Morton , Arnaldo Carvalho de Melo , Jiri Olsa , "ak@linux.intel.com" Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1266 Lines: 32 On Fri, Mar 15, 2013 at 9:31 PM, Greg KH wrote: > > On Fri, Mar 15, 2013 at 02:26:07PM +0100, Stephane Eranian wrote: > > > > This patch fixes a kernel crash when using precise sampling (PEBS) > > after a suspend/resume. Turns out the CPU notifier code is not invoked > > on CPU0 (BP). Therefore, the DS_AREA (used by PEBS) is not restored properly > > by the kernel and keeps it power-on/resume value of 0 causing any PEBS > > measurement to crash when running on CPU0. > > > > The workaround is to add a hook in the actual resume code to restore > > the DS Area MSR value. It is invoked for all CPUS. So for all but CPU0, > > the DS_AREA will be restored twice but this is harmless. > > > > Reported-by: Linus Torvalds > > Signed-off-by: Stephane Eranian > > --- > > Is this needed for the 3.8 or older kernels as well? > I suspect so. If CPU0 is not covered by the cpu notifiers then yes, the patch is needed. > > thanks, > > greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/